Additive manufacturing of metallic components – Process, structure and properties

Elements Of X Ray Diffraction

Welding Metallurgy of

Ti–6Al–4V parts made using additive manufacturing processes such as selective laser melting (SLM) and electron beam melting (EBM) are subject to the inclusion of defects. This study purposely fabricated Ti–6Al–4V samples with defects by varying process parameters from the factory default settings in both SLM and EBM systems. Process parameters are classified according to their tendency to create certain types of porosity. Finally, defect characteristics are discussed with respect to defect generation mechanisms; and effective process windows for SLM and EBM system are discussed.

Analysis of defect generation in Ti–6Al–4V parts made using powder bed fusion additive manufacturing processes

Influence of Defects on Mechanical Properties of Ti-6Al-4V Components Produced by Selective Laser Melting and Electron Beam Melting

A three-dimensional (3-D) finite element model has been developed to simulate the coupled thermal-mechanical fields in ultrasonic welding of aluminum foils. Transient distributions and evolution of the in-process variables, including normal stress, shear stress, slide distance, heat generation, temperature, and plastic deformation on the contact interface, and their interactions have been studied in detail. The von Mises plastic strain from the simulation has been correlated with the measured bonded area of ultrasonic joints. A possible mechanism for ultrasonic bond formation is proposed. The severe, localized, plastic deformation at the bond region is believed to be the major phenomenon causing bond formation in ultrasonic welding.

A Coupled Thermal-Mechanical Analysis of Ultrasonic Bonding Mechanism

Characterization of as-welded microstructure of heat-affected zone in modified 9Cr–1Mo–V–Nb steel weldment

Effect of Post-Weld Heat Treatment on Toughness of Heat-Affected Zone of Grade 91 Steel

GTD-111 directionally solidified superalloy was repaired by the Nd:YAG laser based laser-engineered net shaping (LENS) process. Selection of process parameters are discussed against the formation of deposits and occurrence of defects. Formation of microfissures, porosity, lack of fusion, and stray crystals in the deposit zone was studied. It was identified that formation of stray crystals in the directionally solidified alloy could be due to two types of sources: the shape of the melt pool, and the existence of second-phase particles at the melt pool fusion boundary.

Leijun Li

Papers

A Coupled Thermal-Mechanical Analysis of Ultrasonic Bonding Mechanism

Characterization of as-welded microstructure of heat-affected zone in modified 9Cr–1Mo–V–Nb steel weldment

Effect of Post-Weld Heat Treatment on Toughness of Heat-Affected Zone of Grade 91 Steel

Repair of directionally solidified superalloy GTD-111 by laser-engineered net shaping

Corrosion resistance of pulsed laser-treated Ti–6Al–4V implant in simulated biofluids